Seat and back structure for chairs

ABSTRACT

A chair having seat, back and connecting portions such as arms, preferably formed of a single sheet of bendable or foldable material. All surfaces of the chair are of the types of those ruled surfaces which are developable. Such surfaces are either: (a) plane; or, (b) single-curved surfaces, namely, cylindrical, conical and convolute; or, (c) combinations of (a) and (b). The entire structure is characterized by the absence of any surfaces which are nondevelopable, whereby starting with a flat, bendable or foldable, integral sheet of material a chair may be formed without stretching, crumpling or tearing the sheet. The thus formed structure will receive surface treatment material in sheet form which will lie thereon in mutual conformity therewith, likewise without stretching, crumpling or tearing.

United States Patent [191 Speidel July 17, R973 SEAT AND BACK STRUCTURE FOR CHAIRS [76] Inventor: John A peidel, 7955 llpper River Road, Mainesville, Ohio 45 039 [22] Filed: Aug. 23, 1971 [211 App]. No.: 173,800

Primary Examiner-Casmir A. Nunberg Attorney-Jennings, Carter & Thompson ABSTRACT A chair having seat, back and connecting portions such as arms, preferably formed of a single sheet of bendable or foldable material. All surfaces of the chair are of the types of those ruled surfaces which are developable. Such surfaces are either: (a) plane; or, (b) singlecurved surfaces, namely, cylindrical, conical and convolute; or, (c) combinations of (a) and (b). The entire structure is characterized by the absence of any surfaces which are nondevelopable, whereby starting with a flat, bendable or foldable, integral sheet of material a chair may be formed without stretching, crumpling or tearing the sheet, The thus formed structure will receive surface treatment material in sheet form which will lie thereon in mutual conformity therewith, likewise without stretching, crumpling or tearing.

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Attorneys SEAT AND BACK STRUCTURE FOR CHAIRS My invention relates to seating furniture such as chairs, settees and the like.

In this art it heretofore has been proposed to make chairs having seat, back and connecting portions such as arms by bending or folding a plane sheet of material such as sheet metal. However, in all such constructions known to me, the rule lines of the chair surfaces, or images of those lines projected on the developed pattern, extend fromedge to edge of the chair contour or extend from edge to edge of the developed pattern, respectively; or, the rule lines of the chair surfaces meet a straight line or lines upon the contour whose projected images extend from edge to edge of the developed pattern. Byway of example, see Saarinen US. Pat. No. 2,541,835. Such construction is objectionable from several standpoints including the cost of labor required for extensive pre-configuration of the blank, the waste of material, the necessity of fastening the resultant seam, and the decrease in strength of the finished product.

My invention contemplates a chair seat, back and arm structure which is formed from a plane sheet of material such as sheet metal. I have discovered that configurations suitable for chair structures may be formed by bending and folding such sheet without stretching, crumpling or tearing thus forming developable ruled surfaces for the component surfaces of the configurations as distinguished from other surfaces which. are not developable such as ruled warped sur faces and double curved surfaces. The kinds of ruled surfaces which are developable into a flat sheet include surfaces technically defined as: (a) plane surfaces, namely, those surfaces generated by a straight line moving so as to touch two other intersecting or parallel straight lines or a plane curve; or (b) single-curved surfaces, namely surfaces in which the elements (generatrices) are parallel-(cylindrical surfaces), intersect at a common point (conical surfaces), min which consecutive elements intersecttwo and two (convolute surfaces). (See A Manual of Engineering Drawing For Students and Draftsmen, Thomas E. French, 7th Edition, 1947, page 434; The Encyclopedia Britannica, 1958, Volume 7, page 256, Volume 7, pages 365-367,

and Volume 2], page 589.) By the exclusive use of these surfaces which are developable, and by not allowing the formation of any undevelopable surfaces, my improved chair structure may be economically and simply formed, is extremely strong even though formed of relatively thin material and affords a large number of pleasing, utilitarian chairs. Since the entire structure is developable, surface treatment such as cloth, sheet plastic" material and the like may be applied thereto, likewise without the necessity of stretching, crumpling orgoring. Further, by followingthe teachings of my invention chair structures may be formed of sheet mate rial which later may be rigidized.

My invention contemplates chair structures of the character designated in which there may conveniently .be provided folded or lappedportionsfor the. attachment of legs, pedestals or the like, thus to complete the chair.

My invention has for an object, also, the provision of chairs of the character designated which may be formed with or without arms and which may have convex, concave or flat seats and back portions, or combinations of these configurations while maintaining in all of them the aforementioned characteristics of developable surfaces throughout.

Generally stated, I carry out my invention by first peripherally shaping the sheet of material to provide the chair seat, back and arm shapes and relative dimensions desired. The sheet is now bent or folded along predetermined lines so selected as to form one, some, or a combination of the types of developable ruled surfaces mentioned above. In every case it will be found that there are produced either plane surfaces, conical surfaces,'or cylindrical surfaces, or convolute surfaces, wherein the generatrices of each type surface meet within the confines of the sheet at: (a) a point or points; ([7) a straight line or lines, one end at least of each of which lines terminates short of the edge of the sheet, namely within thesheet; (c) a curved line or lines; or (d) various combinations of points as in (a), above, straight lines as in (b), above, or curved lines as in (6), above. i

In summary, therefore, relative to the objects of my invention I propose a chair seat, back and arm structure in which every part of the same is made up of the various ones of the fully developable surfaces technically and generically termed developable ruled surfaces, whereby the same may be bent without in any way stretching, crumpling, or tearing the sheet.

Chairs and blanks for forming the same embodying FIGS. 4 to 6, inclusive,are figures corresponding to FIGS. 1 to 3, inclusive, and showing a different form of chair and blank;

FIGS. 7 to 9, inclusive, are views corresponding to FIGS. 1 to 3, inclusive, and showing another form of chair;

FIGS. 10 to 12, inclusive, are views corresponding to FIGS. 1 to 3, inclusive, and showing still another form of chair;

FIGS. 13 to 15, inclusive, are views corresponding to FIGS. 1 to 3, inclusive, and showing still another form of chair;

FIGS. 16 to 18, inclusive, are views corresponding to FIGS. 1 to 3, inclusive, and showing still anotherform of chair; and

FIGS. 19 to 21, inclusive, areviewscorresponding to FIGS. 1 to 3, inclusive, and showing still another form of chair. I

Referring now to the drawings" and particularly to FIGS. I, 2 and 3, I show a chair 10 which is formed from a single, unitary, sheet of material such as sheet metal. The chair isprovided with a seat I] and a back 12. In the case shown the seat 11 is composed of a slightly concave and convex section joined to the concave back 12 by two conicalsections 13 and 14. The conical sections 13 and 14 are folded along the lower lines 16 to provide means for attachment of a supporting leg structure indicated at 17.

It will be seen that by bending along the curved line 18 and the straight lines 16 and .21, as shown on the blank, FIG. 3, the chair shown in FIGS. 1 and 2 is produced. As illustrated, the back 12 is slightly concave and the seat 11 is slightly concave in the center and slightly convex at the sides as viewed from the top or seating surface of the chair. It is to be particularly noted that if folded or bent in accordance with the showing of these figures the material of the sheetis in no way stretched, crumpled, or torn since all sections are ruled surfaces of the kind which are fully developable. It will further be seen that any of the straight lines, such as 16 and 21, about which the material is folded have at least one of their ends lying within the confines of the sheet.

Referring now to FIGS. 4 to 6, inclusive, I show a wing back arm chair indicated generally by the numeral 22. Referring particularly to FIG. 6 the blank is peripherally contoured to provide, when bent as will be explained, a wing back arm chair. The folding of the sheet is from two points within the sheet and along three curved fold lines. Thus, the seat portion 23 is bounded by the fold lines 24 and 26, these being straight lines, and the curved fold line indicated at 27. The back proper indicated by the numeral 28 is flat and is joined to the bottom by a partially cylindrical section lying in the area indicated by numeral 29.

The wing or side sections 280 and 28b are curved to wrap around the flat portion'28, the curvature commencing generally along the lines 31. The wing sections 28a and 28b thus are partial cylinders bent forward from the back portion 28.

The arms 32 and 33 are partial truncated cones which are bent forward from the sections 29 and sections 28a and 28b, respectively, along the curved fold lines 34 and 36.

The depending flat sections 37 and 38 are formed between the straight lines 24 and 26 and the respective curved lines 34 and 36. These sections are bent back upon themselves as indicated to provide a space to receive a supporting leg structure 39.

In viewing the chair of FIGS. 4 to 6, it will be seen that again, wherever there are any straight lines such as the lines 24 and 26 and the straight extensions 34a and 36a of the curved lines 34 and 36, at least one end of each of these straight lines lies within the confines of the sheet. Each of these straight lines has an end lying within the confines of the sheet. It will further be noted that there is no stretching, crumpling, or tearing of the sheet, when forming the chair as shown.

Referring now to FIGS. 7 to 9, inclusive, I show another chair made according to my invention and indicated generally by the numeral 41. This is a high back arm chair and in general it can be described as being constructed by folding and bending in more than one direction and from six points within the sheet and along five curved fold lines. Viewing FIG. 9, a slightly convex and concave seat portion 42 is defined by the side, straight lines 43 and 44 and the curved, back joining line 46. The arms of the chair 47 and 48 are defined by curved lines 49 and 51 and by other curved lines 52 and 53 which connect to the upper ends of the curve lines 49 and as shown in FIG. 9. The juncture of these lines is indicated in FIG. 7 by the numerals 54 and 56.

The back proper, in its upper section 57 is flat, while the seat 42 is slightly concave in the center and convex at the sides as viewed in plan. However, the side or wing portions which connect the arms with the flat portion 57 of the back, and indicated at 58 and 59, are curved forwardly as indicated.

The chair now being described thus comprises a back portion proper with a back section 57 and forwardly extending, curved sections 58 and 59, together with a slightly concave-convex seat portion 42. The arms proper are partial cylinders. It will also be noted that downwardly extending strengthening flanges 61 and 62 are provided between the fold lines 43 and 44 and other straight lines 63 and 64.

Like the modifications so far described all the surfaces are plane or single-curved, there being no undevelopable surfaces in any part of the chair. Again, there is no stretching, crumpling or tearing of the sheet and starting with the circular blank as shown in FIG. 9 I am able to produce the chair shown. By the expression without stretching, crumpling, or tearing," I do not imply the elimination of that which occurs transversely across a bend in material of necessity having thickness, known'to those versed in the art as crowding of the material. (See French, page 435, line 23). If desired, supporting structure such as legs 66 may be attached as illustrated. In practice I find that a chair constructed in accordance with FIGS. 7 to 9, inclusive, is extremely strong because the provision of the arm portions which are concave as viewed from the top afford considerable strength to the structure as a whole.

In FIGS. 10 to 12, inclusive, I start with a circular blank to produce the chair indicated generally by the numeral 67. In this instance I provide a chair with a generally flat central back portion 68 with forwardly curved wing sections 69 and 71 and with a rather unusual and ornate arm structure. That is to say, the arms 72 and 73 are formed by bending or folding the material along the pair of curved fold or bend lines indicated at 74 and 76. This produces the flat section 68 for the back and a flat section 77 for the bottom or seat and at the same time produces the conical ann sections which are truncated forwardly as indicated by the lines 78 and 79. This results in a cylindrical section located generally in the area indicated by numeral which connects the seat and back portions. Supporting legs 81 may be used if desired.

Again, by simple folding, bending and without stretching, tearing or crumpling the sheet the chair of these figures is produced. It will further be noted that with respect to all the modifications of my invention only the very simplest of bending and folding mechanisms are required to bring about the results desired. In other words, I eliminate the requirement for expensive dies, expensive jigs and the like, it being necessary only to provide bending bars, shapes and the like which engage the sheet while holding it generally against follow ing the movable bending or forming tools, whereupon the sheet will take the shapes shown and described.

In FIGS. 13 to 15, inclusive, the chair 82, being a high back, wing chair, has a lower flat back section 83 and a flat seat portion 84.

In this instance the fold and bend lines meet at four points within the confines of the sheet. Thus, as shown on the blank the lower, rectangular flat back panel 83 is bounded by the four straight fold lines 86, 87, 88 and 89. The flat seat is bounded by the lines 89 and the straight lines 91 and 92 and the adjacent peripheral edge of the circular sheet of material. Depending strengthening and connecting portions 93 and 94 are provided between line 91 and another line 96 and between line 92 and another line 97.

The arm portions 98 and 99 are made up of reversely disposed cones, and the uppermost of these cones merges into another conical section which forms the forwardly projecting, curved wing parts 101 and 102 of the back. it will be seen that these cones have their apices at the points 103 and 104, namely,-at the upper corners defining the lower rectangular flat back section 83. Again, suitable leg structure 106 may be used if desired.

With the chair just described it may also be desirable to curve downwardly, at the front of the seat 84, a sec tion indicated at 107, and this itself is merely a section of a cylinder, convex as viewed from the seating surface of the chair.

it is to be noted that the lines 96 and 97 as well as the lines 91 and 92 meet at the respective lower corners 103 and 109 of the rectangular back section 83. Thus, again, any straight lines about which the sheet is formed have at least one end lying within the confines of the sheet. Furthermore, instead of using soft or radiused bends, it will be seen that by bending along sharp lines a similar chair could be formed consisting of several flat surfaces.

Referring now to FIGS. 16 to 18, inclusive, 1 show a high back chair which has reversely curved arm sections joining the back to the seat. Thus, the chair 111 has a generally flat back section 112 and a generally flat seat section 113. The seat and back are joined with a fold or bend along line 114. The reversely curved arms 116 and 117 are formed from the side sections 118 and 119 of the blank and they join the back along the fold or bend lines 121 and 122 and join the seat along the fold or bend lines 123 and 124.

It will also be seen that a portion of the blank sections 118 and 119, where they join the back, are folded or curved around to provide slightly forwardly extending wing sections 126 and 127.

In folding this sheet of material'to make the chair shown it will be seen that all of the major folds, being along the lines as indicated, converge to the respective points 128 and 129. The arms 116 and 117 thus are in the shape of a pair of partial cones, the apices of which originate from the respective points 128 and 129 and the uppermost which in. the sense of vertical direction in the chair is convex whereas the lowermost ones of which are concave. Again, no tearing, stretching, or crumpling of the, sheet occurs when making the chair of these figures, as is true with them all. Legs 13] may he provided.

Referring now to FIGS. 19 to 21, inclusive, 1 show a chair 132 provided with a seat portion 133 and a slightly concave back section 134. The back may have forwardly turned wing sections or portions 136 and 137.

This chair is formed by bending generally along the lines 138, 139, 141 and 142, all of these lines coming to a common point 143 within the confines of the sheet. Furthermore, in order to attach a suitable supporting structure 144 l reversely bend the material to provide the depending generally triangular shaped section 146, the apex of which also emanates from the point 143. In other words, the seat portion is interrupted by the downfold in order to support the chair from the structure shown.

The seat 133 has what might be called wing sections 1330 and 13312 and these result from the shape of the blank with which one starts to make this chair. It will be noted that the seat wing sections 133a and 13312 join the wing sections 136 and 137 by conical sections, the apices of which also emanate from the point 143.

ln view of the foregoing it will be seen that 1 have devised an improved chair or like article of seating furni ture. With any of the modifications disclosed, and with many more, which, in view of my invention will be apparent to those skilled in the art, one may start with a unitary sheet of material such as sheet metal and by the proper folding as disclosed herein produce chairs of various shapes, sizes, configurations and designs. With all of my improved chairs, if manufactured in accordance with my invention, there is no stretching, tearing, or crumpling of the sheet itself. Furthermore, it is possible to start with a sheet of material, form the chair, temporarily support it and then rigidize the sheet, thus toprovide what might appear, after manufacture, to be a molded chair.

As will be understood, my invention is characterized by the fact that nowwhere in any of the various surfaces are there any shapes, contours or layouts which are not fully developable, namely, which are not in fact either flat surfaces, conical surfaces, cylindrical surfaces, or convolute surfaces. My improved chair is thus characterized by the presence of all developable surfaces and the complete absence of all surfaces which are nondevelopable. Just as one may start with any of the chairs disclosed, in completed form, and again flatten the sheets, the reverse is true so long as the surfaces in truth are developable.

In all cases rule lines of the surfaces comprising the chair contour meet upon the contour and when the images of such rule lines are projected upon the pattern from which the chair is formed, these images also meet on the pattern. Further, in the contour and on the pat tern the lines and their projected images meet at other than a straight line which extends from edge to edge of the contour and pattern, respectively. Amplifying the statements just made and referring by way of example to FIGS. 7 to 9, inclusive, it will be seen that the straight lines 43 and 44, while extending from one edge of contour and pattern, have ends whichterminate within the confines of the contour of the chair and the perimeter of the pattern. Lines 43 and 44 in MG. 9 are the projected images of lines 43 and 44 in FIG. '7 and this is true of all the lines in all the modifications shown. In none of the prior art chairs which are devel opable from plane and single-curved surfaces do rule lines and their images when projected on the pattern meet upon the contour and pattern, respectively, at a point on the contour and pattern, respectively, at a straight line one end of which terminates short of the edge of the contour and pattern, respectively, ora curved line upon the contour and pattern, respectively.

In actual practice my invention has proven to be extremely satisfactory and I am able to provide an enormous number of pleasing and very strong chair back and seat structures. The connecting portions such as the arms of course add strength and as shown may be provided both for appearance and utility.

While 1 have shown my invention in several forms, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modifications without departing from the spirit thereof.

What I claim is:

1. In a chair,

a. seat, back and connecting sections,

b. the entire seat, back and connecting sections being developable to a unitary flat pattern,

c. said seat, back and connecting sections being ruled surfaces in which rule lines thereof meet upon the contour of the chair, the images of said rule lines when projected on the pattern meeting on the pattern,

d. rule lines of the contours and the images thereof when projected on the pattern meeting at other then a straight line extending from edge to edge of the contour and pattern, respectively, and

e. the seat, back and connecting sections thus formed being self sustaining and load carrying.

2. A chair as defined in claim 1 in which rule lines of the surfaces comprising said contour and the images thereof projected on the pattern meet upon the surfaces of the contour and pattern at a point upon the contour and pattern, respectively, within the confines of the contour and pattern.

3. A chair as defined in claim 1 in which rule lines of the surfaces comrising said contour and the images thereof projected on the pattern meet upon the surfaces of the contour and pattern, respectively, at a straight line, one end at least of which terminates within the contour and pattern short of the edges thereof.

4. A chair as defined in claim I in which rule lines of the surfaces comprising said contour and the images thereof projected on the pattern meet upon the surfaces of the contour and pattern, respectively, at a curved line upon the contour and pattern, respectively.

5. In a chair,

a. seat, back and arm structure formed from a unitary sheet of bendable material,

b. saidsheet being bent along a combination of curved and straight lines, the latter of which have at least one of their ends terminating within the confines of the sheet,

c. all portions of said structure being made up of ruled surfaces which are developable, whereby the entire structure may be formed from said sheet without stretching, tearing or crumpling the sheet, and

d. the seat, back and connecting sections thus formed being self sustaining and load carrying.

6. A chair as defined in claim 5 in which said structure may have surface treatment material in sheet form applied thereto and which lies in mutual conformity to the respective surfaces of the structure without stretching, crumpling, or tearing said surface treatment sheet. =l=

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTICN Patent No. '5 H 6 39); Dated July 17, 1973 Inventor(s) John A peidel It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 6, line L B, after the word 'pattern" insert and this is true of all straight lines extending from an edge of contour and pattern in all the modifications shown line If), cancel "and" second occurrence; cancel line 50; line 51 cancel 'shown" Column 7, line 3, element ((3), the word "then" should read than Signed and sealed this 26th day of March l97L (SEAL) Attest:

EDWARD M..FLETCHER,JR. C. MARSHALL DANN Attesting Officer Commissioner of Patents USCOMM-DC GOS'IQ'POD 9 U.5 GOVERNMENT PRINTING OFFICE: I9! 0-360-33 FORM PC3-1050 (10-69) 

1. In a chair, a. seat, back and connecting sections, b. the entire seat, back and connecting sections being developable to a unitary flat pattern, c. said seat, back and connecting sections being ruled surfaces in which rule lines thereof meet upon the contour of the chair, the images of said rule lines when projected on the pattern meeting on the pattern, d. rule lines of the contours and the images thereof when projected on the pattern meeting at other then a straight line extending from edge to edge of the contour and pattern, respectively, and e. the seat, back and connecting sections thus formed being self sustaining and load carrying.
 2. A chair as defined in claim 1 in which rule lines of the surfaces comprising said contour and the images thereof projected on the pattern meet upon the surfaces of the contour and pattern at a point upon the contour and pattern, respectively, within the confines of the contour and pattern.
 3. A chair as defined in claim 1 in which rule lines of the surfaces comrising said contour and the images thereof projected on the pattern meet upon the surfaces of the contour and pattern, respectively, at a straight line, one end at least of which terminates within the contour and pattern short of the edges thereof.
 4. A chair as defined in claim 1 in which rule lines of the surfaces comprising said contour and the images thereof projected on the pattern meet upon the surfaces of the contour and pattern, respectively, at a curved line upon the contour and pattern, respectively.
 5. In a chair, a. seat, back and arm structure formed from a unitary sheet of bendable material, b. said sheet being bent along a combination of curved and straight lines, the latter of which have at least one of their ends terminating within the confines of the sheet, c. all portions of said structure being made up of ruled surfaces which are developable, whEreby the entire structure may be formed from said sheet without stretching, tearing or crumpling the sheet, and d. the seat, back and connecting sections thus formed being self sustaining and load carrying.
 6. A chair as defined in claim 5 in which said structure may have surface treatment material in sheet form applied thereto and which lies in mutual conformity to the respective surfaces of the structure without stretching, crumpling, or tearing said surface treatment sheet. 